Bridge system adapted for promoting sedimentation

Abstract

A system providing environmentally friendly pathway tunnel utilizes a bottom configuration with multiple elongated beams and slots. One or more of the beams includes upstanding sedimentation members that are spaced apart along a span of the tunnel. The system interacts with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.

Claims

1. A surrounded water flow pathway tunnel adapted to produce an environmentally-friendly tunnel bottom, the pathway tunnel comprising: a bottom configuration formed by a plurality of concrete beams extending in a spanwise direction from one side of the pathway tunnel to another side of the pathway tunnel and that are spaced apart along a depth of the pathway tunnel to define a plurality of elongated through-openings for interacting with flowing water and earthen material in flowing water to enhance capture and settling of earthen material along the pathway tunnel, wherein two or more concrete beams include a plurality of upwardly-projecting sedimentation members spaced apart in the spanwise direction to define gaps between the sedimentation members, wherein a depthwise center-to-center spacing along the pathway tunnel between concrete beams having sedimentation members is between about thirty percent and about seventy percent of a span of the pathway tunnel, wherein multiple concrete beams lack any sedimentation members, wherein for each concrete beam that includes sedimentation members, at least one sedimentation member located on the concrete beam has a height that is greater than a height of another sedimentation member located on the concrete beam; wherein, for each concrete beam that includes sedimentation members, at least one sedimentation member located toward one of the sides of the pathway tunnel has a height that is greater than a height of another sedimentation member located towards a spanwise center of the pathway tunnel.

2. The surrounded water flow pathway tunnel of claim 1 wherein each sedimentation member has a height that is between about ten percent and about twenty-seven percent of a clear height of the pathway tunnel at top dead center.

3. A surrounded water flow pathway tunnel adapted to produce an environmentally-friendly tunnel bottom, the pathway tunnel comprising: one end of the pathway tunnel located upstream along a natural water path and an opposite end of the pathway tunnel located downstream along the natural water path; a bottom configuration of the pathway tunnel formed by a plurality of concrete beams extending in a spanwise direction across the pathway tunnel and spaced apart along a depthwise direction of the pathway tunnel to define a plurality of through-openings extending in the spanwise direction, wherein at least one concrete beam includes a plurality of upwardly-projecting sedimentation members spaced apart in the spanwise direction to define gaps between the sedimentation members, wherein at least one sedimentation member located towards one side of the pathway tunnel has a height that is greater than a height of another sedimentation member located towards a spanwise center of the pathway tunnel.

4. A surrounded water flow pathway tunnel adapted to produce an environmentally-friendly tunnel bottom, the pathway tunnel comprising: a bottom configuration formed by a plurality of concrete beams extending in a spanwise direction and that are spaced apart along a depth of the pathway tunnel to define a plurality of through-openings, wherein at least one of the concrete beams includes a plurality of upwardly-projecting and fixed sedimentation members spaced apart in the spanwise direction to define gaps between the sedimentation members, and at least one concrete beam lacks any sedimentation members, wherein sedimentation members that are located on the at least one concrete beam toward sides of the pathway tunnel have heights that are greater than a height of at least one sedimentation member located on the at least one concrete beam toward a spanwise center of the pathway tunnel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of one embodiment of a four-sided bridge unit;

(2) FIG. 2 is an end elevation of the bridge unit of FIG. 1;

(3) FIG. 3 is a cross section along line 3-3 of FIG. 2;

(4) FIG. 4 is bottom view of the bridge unit of FIG. 1;

(5) FIG. 5 is a cross-sectional view of two bridge units of FIG. 1 arranged edge to edge;

(6) FIG. 6 is an enlarged partial view of the cross-section of FIG. 5;

(7) FIG. 7 shows a partial cross-section of an embodiment of a unit with both upstream and downstream facing lips;

(8) FIG. 8 shows a partial cross-section of an embodiment of a unit in which the beams all have a common height;

(9) FIGS. 9 and 10 show perspective views of another embodiment of a four-sided bridge unit in which continuous haunches are provided in the corners where the bottom wall meets the side walls;

(10) FIG. 11 is a perspective view of yet another embodiment of a four-sided bridge unit;

(11) FIG. 12 is an end elevation of the bridge unit of FIG. 11;

(12) FIG. 13 is a cross section along line 13-13 of FIG. 12;

(13) FIG. 14 is bottom view of the bridge unit of FIG. 11;

(14) FIG. 14A is a partial cross-section along line 14A of FIG. 14;

(15) FIG. 15 is a perspective view of still another embodiment of a four-sided bridge unit;

(16) FIG. 16 is an end elevation of the bridge unit of FIG. 15;

(17) FIG. 17 is a cross section along line 17-17 of FIG. 16;

(18) FIG. 18 is bottom view of the bridge unit of FIG. 15;

(19) FIGS. 19A-B show another embodiment of a bridge unit;

(20) FIG. 20A-C show another embodiment of a bridge unit;

(21) FIG. 21A-C show another embodiment of a bridge unit;

(22) FIG. 22 shows a plurality of four-sided units arranged along a water flow path;

(23) FIG. 23 shows a schematic end elevation of the system of FIG. 22 as buried;

(24) FIG. 24 shows a perspective view of another embodiment of a bridge unit;

(25) FIG. 25 shows an end view of the bridge unit of FIG. 24;

(26) FIG. 26 shows a side view of the bridge unit of FIG. 24;

(27) FIG. 27 shows a perspective view of a bridge system formed by abutting multiple bridge units of the type shown in FIG. 24;

(28) FIG. 28 shows a side view of two abutting bridge units;

(29) FIG. 29 shows a side view of three abutting bridge units; and

(30) FIG. 30 shows an end view depicting resulting sedimentation within the pathway tunnel.

DETAILED DESCRIPTION

(31) Referring to FIGS. 1-4, a four-sided precast concrete bridge unit 10 is shown. In the illustrated embodiment bridge unit 10 is formed by a generally horizontal extending bottom wall 12, substantially vertically upward extending side walls 14 and 16 at the ends of the bottom wall and a top wall 18 having a generally arch-shaped configuration. However, four sided bridge units having top walls other than arch-shaped (e.g., flat top walls) are also contemplated. Likewise, side walls other than vertical are possible. As used herein, the terms length and span of an individual unit or portions of the unit refers to a horizontal dimension extending parallel with the direction of arrow 20 (which is substantially perpendicular to a horizontal through axis 22 of the unit) and the terms width and depth of the individual unit or portions of the unit refer to a horizontal dimension extending parallel to the through axis 22. As used herein the term arch and arch-shaped when referring to the top of an arch unit means a curved shape (including constant radius curves, curves with multiple radii, curves with continuously varying radius) or any top wall shape that is higher in the middle of the top wall as opposed to where the top wall meets the side walls (e.g., an inverted V-shape or a combination of three or more planar segments angularly arranged with respect to each other to produce a vaulted top wall or a combination of curved segments and flat segments that produce a vaulted top wall).

(32) The bottom, top and side walls are preferably precast as a single monolithic structure in a single casting operation. However, in certain implementations, one or more walls may be cast separately and then connected together by suitable connecting structure (e.g., reinforcing bars or by casting one or more elements separately and then placing that cast element in the formwork that is used to cast the final structure).

(33) The bottom wall 12 of the unit 10 is shaped and configured to facilitate both sedimentation within and passage of marine life once the unit is installed. Specifically, the bottom wall 12 includes a plurality of elongated, spanwise extending through openings that extend completely through the thickness of the bottom wall 12. As shown, each elongated opening 24 has a length L.sub.O that is at least about sixty percent of the overall width of the unit L.sub.U (e.g., L.sub.O is at least about 70% of L.sub.U, such as for example, between 80% and 95% of L.sub.U). However, other variations are possible. Intermediate beams 26 separate the elongated openings 24 and serve to maintain a rigid connection between the lower ends of the side walls 14 and 16. Edge located beams 28 are also provided, thereby providing a continuous peripheral support surface at the lower side of the bottom wall. The lower surface of each beam 28 is preferably in common plane with the continuous peripheral support surface to provide added stability and distribution of loads. As shown, roughly about 40% to 60% (e.g., about 45% to 55%) of the lower side of the bottom wall makes up the support or resting surface of the bridge unit and the remainder (about 60% to 40%) is open via the openings 24. However, other variations are possible. Lengthwise extending reinforcement may be provided in each of the beams for structural integrity, with some continuity provided between that reinforcement and the reinforcement of the vertical side walls.

(34) As seen in FIG. 3, where the anticipated water flow direction through the bridge unit is shown by arrow 30, the combination of the beams 26, 28 and the openings 24 are configured to promote sedimentation at the bottom of the bridge unit. Specifically, the beams 26 and one of the beams 28 are formed with a lip structure 32 and 34 that overhangs the adjacent opening 24 and extends from the beam in an upstream direction. Also, one or more of the beams 28 has a thickness or height that exceeds that of the adjacent beams 26 and/or 28. The effect of this configuration is best described with reference to FIGS. 5 and 6, where FIG. 5 shows two units 10 in edge to edge relationship as such units would typically be installed on a job site and FIG. 6 shows an enlarged partial view with a flow pattern.

(35) As seen in FIG. 5, the edge located beams 28 (located at the upstream flow edge of the units) lack any upstream facing lip structure while the edge located beams 28 (located at the downstream flow edge of the units) incorporates an upstream facing lip structure. In this manner, when two units 10 are installed edge to edge, there is no lip structure to interfere with the placement and the adjacent beams 28 and 28 combine to form effective beam that is similar in overall configuration and size to intermediate beam 26. In this regard, the width of the beam structures 28 and 28 is preferably smaller than the width of beam structures 26 and 26 (e.g., on the order of about 50% to about 60% of the width of beam structures 26 and 26) so that the overall width of the effective beam is more consistent with the overall width of the beams 26 and 26. The height of beams 26 is greater than the height of beams 26, 28 and 28 as shown. Beams 26, 28 and 28 have the same thickness or height and beams 26 may have a thickness or height that is about 110% to about 140% greater (e.g., about 120% to about 130% greater). However, variations are possible. The width W.sub.L of the lip structure may be on the order of about 10% to 20% of the overall width W.sub.O of the opening 24. In the illustrated embodiment, a tapered surface 36 connects the vertical side surface 38 of the beam with the protruding edge of the lip.

(36) Referring to FIG. 6, as water flows through the units the higher beams tend to reduce the velocity in the vicinity 40 of an opening 24 which tends to cause sediment to drop out of the flow and into the opening. The lip structure 32 helps prevent washout of any sediment that builds up in the openings 24. The lip structures 32 and 34 of the shorter beams 26 and 28 also help prevent washout in respective openings and creates respective areas 42 and 44 of lower velocity that can promote sedimentation.

(37) In the illustrated embodiment, the connection of every other beam to the vertical side wall includes a haunch 46, which may include reinforcement, to resist the moment loads in the corners. Placing the haunches in a spaced apart manner, rather than providing a continuous haunch, can also help promote sedimentation. However, continuous haunches are also contemplated for some applications, as reflected in the embodiment of FIGS. 9 and 10. In this embodiment, the relative length of the slotted openings 24 (as compared to overall length of the unit) is smaller than that shown in FIG. 4 in order to accommodate the haunch 46. Moreover, FIGS. 9 and 10 show a four-sided bridge unit with a flat top wall structure rather than an arched top wall structure.

(38) While the embodiment of FIGS. 1-6 contemplates upstream facing lips only, in an alternative embodiment downstream facing lips may also be provided on the beams as shown in FIG. 7. Likewise, embodiments in which all the beams have a common height are contemplated, as shown in FIG. 8.

(39) Referring again to FIGS. 1, 2 and 4, and regardless of the relative height of the plurality of beams, each of the beams may be formed with a section 48 of reduced thickness to create a low flow channel through the unit, making it easier for marine life (e.g., fish) to travel through the unit. The reduced thickness sections 48 may be formed without any lip structures.

(40) An alternative embodiment of a four-side bridge unit 50 adapted for sedimentation is shown in FIGS. 11-14. As shown, the bottom wall 52 of the bridge unit 50 includes a plurality of openings 54. The openings are arranged in a plurality of lengthwise extending rows 56 and 58, with the rows 56 and 58 arranged in an alternating and staggered relationship that provides some nesting of the openings of one row into the spaces between the openings of another row. The openings are distributed along a lengthwise extending mid-portion L.sub.O of the bottom wall 52 that represents between about 50% to about 80% of the overall length L.sub.O of the bottom wall of the unit. In this manner, the bottom wall lacks any openings in roughly about the first 10% to 25% of the extent of the bottom wall from its ends. Reinforcement 60 may be located in this area for structural integrity. Likewise, as the edges of the bottom wall are continuous, lengthwise reinforcement 62 may be included along such edges as well. About 75% to about 90% of the bottom wall in the mid-portion L.sub.O may be open space, while only about 55% to about 70% of the overall area of the bottom wall (as viewed from the bottom) may be open space. As shown in FIG. 14A, the openings 54 may include lip structure to promote sedimentation and reduce washout effects. The lip structure may be upstream facing lip structure 66, downstream facing lip structure 64 and/or lengthwise facing lip structure 68.

(41) A further embodiment of a four-sided bridge unit 70 is shown in FIGS. 15-18. In this embodiment the openings 74 of the unit actually include rows of partial openings along each edge. The partial openings 74 are preferably about one half the size of a regular opening such that when one unit is abutted with another unit the partial openings combine to effectively form an opening similar in size and shape to the openings 74. The mid-point arrangement of the openings along the length of the bottom wall 72 may be similar to that of the embodiment of FIGS. 11-14, with reinforcement 76 in the end areas of the bottom wall 72. However, due to the edge openings 74, no reinforcement is provided in the mid-section where the openings are located. The openings 74 of the unit 70 may also include lip structure as described relative to FIG. 14A.

(42) It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. For example, other possible unit configurations are reflected in FIGS. 19A-B, 20A-C and 21A-C. For reference, the unit 90 of FIGS. 19A-B includes lengthwise extending openings 82 having ends adjacent the side walls 84, alternatingly raised 86 and lowered 88 beams and upstream facing lips, with no haunches or gusseting between the bottom wall and the side walls. The unit 90 of FIGS. 20A-C is similar to that of FIGS. 19A-B but also includes reduced thickness sections in the beams to provide a low flow channel 92. The unit 100 of FIGS. 21A-C includes beams and slots with ends spaced from the side walls, and no haunches or gussets, such that the corner areas between the bottom wall and the side walls form low flow areas.

(43) FIG. 22 shows a plurality of four-sided concrete bridge units, which could be any of the unit configurations previously described, in abutting relationship to create a surrounded pathway tunnel 110. One end 112 of the tunnel is located upstream along a water path 114 and an opposite end 116 of the tunnel is located downstream along the water path 114. FIG. 23 shows the units in profile as buried in earthen material 118. FIG. 23 could also represent a series of buried units used for the purpose of storm water collection, with infiltration into the surrounding earth occurring through the openings in the bottom walls of the units.

(44) Referring now to FIGS. 24-28, another embodiment of a bridge system is shown in which each precast concrete bridge unit 200 includes opposed side walls 202 and 204 and a top wall 206, which are shown in transparent outline form to facilitate viewing of the bottom configuration. The bottom configuration of each bridge unit is formed by a plurality of precast concrete beams 210, 212, 214 extending from one side wall 202 to the other sidewall 204. The beams are spaced apart along a depth D.sub.200 of the bridge unit to define a plurality of elongated through openings 216 and 218 for interacting with flowing water 220 and earthen material in flowing water to enhance capture and settling of earthen material. In the illustrated embodiment, each of the plurality of elongated through openings 216, 218 extends from one side wall 202 to the other side wall 204 to provide full span connectivity between a pathway tunnel 224 through the unit and the underlying ground 226 along each elongated through opening 216, 218. Moreover, each elongated precast concrete beam 210, 212, 214 has a bottom side 230, 232, 234 that is in a common plane with a bottom surface of each of the side walls 202, 204 so as to aid in transferring load to ground below the bridge unit.

(45) As shown, at least one elongated precast concrete beam has a configuration that is different than a configuration of another one of the elongated precast concrete beams. In the illustrated embodiment having three beams 210, 212 and 214, the configurations are all distinct in some way. More specifically, beam 210 includes upright sedimentation members 240, whereas beams 212 and 214 do not. Also, the depthwise dimension of beam 212 is larger than the depthwise dimension of both beams 210 and 214.

(46) In preferred implementations the elongated slots 216, 218 are sized such that at least forty percent of the bottom configuration 208 of each bridge unit is open (e.g., at least fifty percent is open).

(47) Referring again to the upwardly projecting sedimentation members 240, such members spaced apart in a spanwise direction DSPAN to define gaps 242 between the sedimentation members 240. Notably, the height of the sedimentation members varies. In particular, more centrally located sedimentation members 240A have heights that are less than heights of the more outward sedimentation members 240B, which in turn have heights that are less than the more outward sedimentation members 240C. In this regard, the height of each sedimentation member is defined relative to the upper surface 244 of the beam (e.g., 210 in this case) from which it extends. In the illustrated embodiment all of the beams 210, 212, 214 all have a common height, resulting in coplanar upper surfaces as between the beams.

(48) By properly configuring and spacing the upright sedimentation members 240, desirable sedimentation can be achieved within a pathway tunnel defined by multiple units, while at the same time facilitating fish passage. In one preferred implementation, each sedimentation member has a height (e.g., H.sub.240Adefined relative to the upper surface of the beam from which it extends) that is between about ten percent and about twenty-seven percent of a clear height of the pathway tunnel at top dead center). In this regard, the clear height of the pathway tunnel is defined as the dimension H.sub.CH between the upper surface of the shortest upright members 240A and the inner surface of the top wall at top dead center of the unit. In a preferred implementation, each gap 242 between the sedimentation members has a horizontal dimension D.sub.G that is between about six percent and about twelve percent of the span D.sub.SPAN of the pathway tunnel 224, while a center-to-center spacing S.sub.CC between adjacent sedimentation members 240 is between about twelve percent and about seventeen percent of the span D.sub.SPAN of the pathway tunnel.

(49) In the illustrated embodiment, at least one of the elongated precast concrete beams (e.g., in this case both beams 212 and 214) lacks any sedimentation members. Utilizing this configuration, a more suitable depthwise center to center spacing D.sub.CC along the pathway tunnel between elongated precast concrete beams 210 having sedimentation members can be achieved, where it is preferred that such spacing D.sub.CC between about thirty percent and about seventy percent of the span D.sub.SPAN of the pathway tunnel. In embodiments where only one beam of each bridge unit includes the sedimentation members and like bridge units are used, the dimension D.sub.CC will generally be the same as the depth D.sub.200 of the bridge units. Where the beam 210 with sedimentation members 240 is located at one end of the bridge unit and a beam 214 with no upright members is located at an opposite end of the bridge unit, upon installation, the beam 210 with sedimentation members will abut against the beam 214 without sedimentation members. Configuring the bridge units such that only one beam has the sedimentation members, and locating that beam at one end of the bridge unit, also facilitates manufacture of the bridge units. More specifically, each bridge unit can be cast on end with top wall and side walls in one pour, and side then beams and baffles cast as a secondary pour. The end baffle configuration/location eliminates the need to form the baffles off the ground, simplifying production.

(50) As noted above, the sedimentation members have different heights. To achieve desirable sedimentation results within the pathway tunnel, the install elevation of the bridge units is desirably matched with the invert of the natural water flow path feeding into the pathway tunnel. More specifically, and referring to FIG. 29, the top surface of the shorter sedimentation units is represented by dashed line 250, which is shown at substantially the same elevation as the invert 252 of the incoming water flow path. Thus, the upper surfaces of the precast concrete beams are all located below the incoming invert 252 at the time of on-site installation of the units.

(51) Utilizing sedimentation members of different heights also facilitates fish passage. In particular, referring to FIG. 30, the resulting sedimentation achieved within the pathway tunnel is depicted as 260, where it is seen that the although the shorter sedimentation members 240A are substantially covered, the taller sedimentation members 240B and 240C are more exposed, meaning that they remain capable of reducing water flow velocity in tunnel regions aligned with such members, creating areas of lower velocity for fish passage.

(52) Other embodiments are contemplated and modifications and changes could be made without departing from the scope of this application. For example, while the primary embodiments contemplate four-sided bridge units it is recognized that other variations could be implemented. For example, the bottom configuration depicted in FIGS. 24-28 could be implemented utilizing a set of precast or cast-in-place bottom modules, and the pathway tunnel 224 completed by other structure such as metal plate of any suitable arch or arch-like configuration.